Water-soluble films are well known in the art. Water-soluble films have many applications, such as packaging materials, wherein the film itself can make up a water soluble packet. These compositions have the advantage that they are easy to dose, handle, transport and store.
Water-soluble packets are well suited for single dose applications wherein the packet encloses a laundry detergent, bleach or other laundry additives, fabric care, dishwashing, hard surface cleaning, beauty care, skin care, other personal care, or food product compositions. Often enclosed in water-soluble packets are active agents that may become unstable in the presence of other active agents, or may cause other ingredients to become unstable, thereby limiting what active agents can be prepackaged together in a single dose form.
The activity of enzymes in previously-known films tended to be low and to decrease with storage time. This loss of activity tended to be especially severe when the enzyme composition included a protease, as the protease can break down itself or other enzymes. In an attempt to compensate for the decrease in enzymatic activity, a large concentration of enzyme had been included in film compositions, and this approach was not always successful in producing a film with at least a moderate activity. Accordingly, it is highly desirable to produce a film that maintains a high level of enzyme activity without requiring starting with a high concentration of enzyme (i.e., high enzyme percent recovery after processing and storage).
Active agents often used as additives in laundry and dishwashing applications include enzymes such as protease, amylase, lipase, and oxido-reductase enzymes, including but not limited to oxido-reductase enzymes that catalyze the formation of bleaching agents. Therefore, a water-soluble film containing enzymes that maintain a high level of activity, especially in the presence of protease, would be advantageous for use in water-soluble single dose packets enclosing detergents or other laundry or dishwashing additives.